Bought 2 of these insulators. They measure approx. 3 1/2-3 3/4" high with a base of 2 1/2" and they are PURPLE! I cannot find any embossing on them , Lots of bubbles in the glass with groove like squiggles.
These are known as "tolls," a telephone style used for local and inter-city lines. Most commonly they're embossed AM. TEL. & TEL. CO.
The unembossed purple varieties aren't common at all (well, any purple is a good find). Usually they sell in the 30-40 range if they're in good shape.
The squiggles you mention are from the glass molding. Molten glass is very thick, like honey, so glass workers often poured a bit too slowly and got a little trickle of glass into the mold first, which cooled a bit. That trickle didn't totally melt into the blob pressed in the mold. It won't affect value but it certainly adds some character to the glass and makes it more interesting for us today, where machine-made glass is so uniform.
I don't usually mention it to people brand-new to insulators (they sometimes get a bit overwhelmed), but insulator collectors identify shapes by Consolidated Design numbers, called "CD" for short. This one's a CD 121.
Great info and news...I paid $1 each for them. There is some chipping on the bottoms but only noticeable if you pick them up and look closely. Otherwise in great condition. Thank you for the information. I knew I could count on this forum. Might be for sale...